The study will be conducted at four major medical centers, including the University of Southern California, the University of Minnesota, the Dana Farber Cancer Institute, and the MD Anderson Cancer Center. Blood and urine samples will be collected from patients undergoing treatment with either cisplatin or aminoglycosides, which are two different drugs known to cause injuries to the proximal tubule of the kidney. Cisplatin is a common chemotherapy drug taken by patients with head and neck cancer. Aminoglycosides are a common antibiotic drug taken by patients with cystic fibrosis.